Reintroduce VisualEditor capability check in mwoffliner once issue in Phabricator:T350117 is fixed

[VadimKovalenkoSNF]

There is a regression with VisualEditor introduced in MW core. Check the related Phab ticket - https://phabricator.wikimedia.org/T350117. Mwoffliner relies on VisualEditor Mediawiki namespace when it comes to testing. More info in #1937 - our first assumption was that the mwoffliner caused this regression because of exceeding MW infrastructure rate limits.

[kelson42]

@VadimKovalenkoSNF Please don't forget to put here the PR to revert, so there is no ambiguity about what to do.

[VadimKovalenkoSNF]

PR that introduces temporary disabling of the VisualEditor capability check - #1941